Apparatus for charging storage batteries.



W. T. HENSLEY.

APPARATUS FOR CHARGING STORAGE BATTERIES.

APPLICATION FILED NOV. 9. 1914.

1 356,228. Patented Feb. 12, 191&

W2 asses. I ZZZ/67622771 UNITED STATES PATENT OFFICE.

WILLIAM T. HENSLEY, 0F BOUNDIBROOK, NEW JERSEY, ASSIGNOR, BY MESNEASSIGN- MENTS, TO BOUND BROOK ENGINE & MFG. 00., A CORPORATION OFDELAWARE.

APPARATUS FOR CHARGING STORAGE BATTERIES.

Specification of Letters Patent.

Patented Feb. 12, 1918.

Application filed November 9, 1914. Serial No. 871,004.

To all whom it may concern:

Be it known that I, WILLIAM T. HENSLEY, a citizen of the United Statesof America, and resident of Boundbrook, Somerset county, New Jersey,(229 Mountain avenue,) have invented a certain new and usefulImprovement in Apparatus for Charging Storage Batteries, of which thefollowingis a specification.

My invention relates to apparatus for charging storage batteries ingeneral, but more particularly to apparatus of this kind in which thegenerator is dependent for its operation upon a variable speed source ofpower, and especially those in which the said source of power is theinternal combustion engine of an automobile or other vehicle. Incharging a storagebattery by a generator driven from the engine of anautomobile, it is desirable to have the generator operate at a constantspeed, or substantially so, under all conditions, so that the chargincurrent will be uniform at all times, without the use of auxiliaryelectrical current regulating apparatus or devices. Some provision,therefore, must be made for insuring a constant speed of the generator,notwithstanding that the speed of the engine varies considerably. Acentrifugal friction clutch may be used for this purpose, but ordinarilya clutch of this kind is subject to some change or variation (when thefriction elements become heated or worn) when in operation. In otherwords, the friction of the parts, with the material or substancesordinarily employed in clutches of this character, tends to increase thewear, and hence a frequent adjustment of the clutch would, under such.conditions, be necessary in order to insure the desired uniformity ofthe charging current. In other words, the generator should run at agiven speed at all times; but with the materials ordinarily used inclutches of this kind, the

friction and resulting wear of the parts is considerable, and frequentustment becomes necessary. Such being the case, it follows that withordinary friction clutches, operating under a constant spring tension,the charging current would have a tendency to change as the clutchbecomes worn, which is very undesirable. In charging storage batteries,it is not only regarded as improper to allow the current to rise, orclimb as it is called, from the beginning of the charge,

but it is also regarded as being beneficial if the current is allowed tofall off or drop appreciably after the starting thereof, and during thecharging period. In other words, the current should not be allowed torise, but should fall away from the maximum current at which thecharging operation commences, as the charging operation progresses.

It is well known to those skilled in the art that if the speed of thegenerator and the strength of the charging current are kept at apredetermined maximum during the entire period of the chargingoperation, gassing or boiling of the battery is likely to result, and asubstantial amount of generated current is wasted. If, however, thegenerator speed is progressively reduced and the length of the chargingperiod increased there will result, a substantial saving of thegenerated current, and the gassing or boiling of the battery will bepractically eliminated.

My invention is especially valuable when used in connection with storagebatteries which, after being used for a short interval of time, areimmediately brought up to their normally full strength, having thecurrent restored by recharging. For instance, when an automobile engineis started, the current from the battery is utilized at a heavy amperagefor a fraction of a minute. Vhen the engine has been started and isrunning, and the battery is being recharged, the amperage of thecharging current will be light as compared to that of the startingcurrent; and it will take a number of minutes to recharge the battery inorder to replenish the amount of current used in starting. At about thetime the full amount of current has been restored to the battery, theclutch will have heated up, thus causing slippage of the clutch parts,and the consequent falling off of the charging current as hereinreferred to.

An object of my invention is, therefore, to provide a centrifugalfriction clutch for use in combination with a source of power ofvariable speed for driving the constant speed generator by which thecurrent is supplied to the storage battery for charging purposes, thesaid clutch being of such character that the heat or wear of thefriction surfaces therein will not cause the generator to run faster,and the wearing elements of the said clutch being of such character thatthe said generator will, in fact, run a little slower, if anything, whenthe clutch becomes highly heated in operation, whereby the chargingcurrent will have no inclination to rise or climb during the chargingoperation.

Another object is to provide a substance or material for the brake bandsof the clutch, of such character that it will impart a high polish tothe revolving brake drum, and serve not only to minimize the wear ofthefriction elements, but also to prevent the generator from speeding upwhen said bands and drum become heated.

To these and other useful ends, my invention consists in mattershereinafter set forth and claimed.

In the accompanying drawings Figure l is a diagram showing a storagebattery charging apparatus embodying the principles of my invention.

Fig. 2 is an enlarged detail view of the centrifugal friction clutchemployed in said apparatus for converting the variable speed of theautomobile engine into a constant speed on the part of the generatorwhich supplies the current to the storage battery during the chargingoperation.

As thus illustrated, the storage battery A may be of any suitable knownor approved character. A constant speed generator 1?, of any suitable ordesired construction, is connected with the storage battery in the usualand well known manner. An. internal combustion engine C, of any suitableform or construction, is connected by a belt a with said generator. Asthus illustrated, the said battery and generator and engine may be thoseordinarily found on automobiles having an electric apparatus forcharging the battery which supplies current for starting and lightingand other purposes. In such case, the said engine is, of course, in thenature of a variable speed source of power, inasmuch as it runs slowlyat times and very fast at other times; and for this reason someprovision must be made for maintaining the speed of the generatorconstant under all conditions and for all speeds of said engine. Forthis purpose, a centrifugal friction clutch D is mounted on the engineshaft and connected by the said belt with a pulley b on the armatureshaft of the generator. The said clutch has a ring d which is fixed onthe engine shaft 0 and is provided with a loose member al which isengaged by the said belt. In order to connect the outer or loose memberal with the engine shaft, brake shoes or bands d are provided andpivoted to the said member al at (P, the other ends of said shoes beingconnected together by a spring device d of any suitable character. Thesaid device d* is adjustable in any suitable manner for the purpose ofvarying the spring tension thereof, and for thereby increasing ordecreasing the pressure of the brake shoes on the ring or drum d,depending upon the speed desired for the generator. Centrifugal forcewill cause the brake shoes or hands (Z to bear with less pressure on thedrum when the engine is running at high speed, than when running at lowspeed, with the result that the speed of the generator is maintainedconstant, notwithstanding the fluctuations of the engine speed. The saidring d is made of metal, as, for example, cast iron or steel, and isprovided with a perfectly smooth periphery upon which the brake shoesbear. Each brake shoe is preferably provided with a face or engagingportion d of a substance which produces a high polish on the peripheryof the ring d, and of such nature that it does not increase the frictionwhen the clutch is operating or becomes highly heated. For this purpose,the wearing portions d of said brake shoes may be made of carbon, suchas ordinary carbon, with the addition of some graphite carbon, such asthat used for electric motor brushes; but the invention is not limitedto this particular substance, as other substances which will minimizethe wear and burnish the periphery of the ring (Z, and which willprevent an increase of friction when heated and during operationthereof, thus insuring against a variation of the speed of thegenerator, may be used for this purpose. As stated, carbon fulfils therequirements in this respect, and in actual practice the friction of theclutch not only does not increase when the parts become heated, but tothe contrary appears to become somewhat less; and the result is that theheating of the clutch not only does not cause the current to rise orclimb during the charging operation, but if anything seems to produce aslight falling off or dropping of the current. Moreover, the burnishingor polishing action is such that wear is greatly reduced, thus makingfrequent adjustments unnecessary. The current measuring instrument E,connected as usual in circuit with the generator and battery, does notindicate any increase of current when the clutch'becomes hot, or afterthe engine has been running for some time. This is for the reason thatthe carbon-tometal wearing elements do not sufi'er an increase offriction when they are heated, but to the contrary seem to produce lessfriction at such time than when the clutch is first operated. Thus asubstance is interposed in the clutch to prevent the heat fromincreasing the friction and to reduce wear, thereby enabling thegenerator to run at constant speed, or even with a slight fallin off inspeed, when driven from a source of power of variable speed.

As stated, there are two reasons why the ordinary friction clutch is notsatisfactory for connecting a. variable speed source of power to anelectric generator. First, the substances or materials ordinarily usedfor a clutch ofthis kind are subjectto excessive wear to an extentrequiring frequent adjustment to compensate therefor; and, second, thesesubstances are affected by heat in a manner that makes the brake shoesslide less readily on the surface of the drum, thereby increasing thespeed of the generator. With my invention, however, both of thesedifliculties are overcome, as the carbon of the brake shoes burnishesthe metal surface of the drum or ring, and the action of the graphite issuch that very little wear occurs; and, what is equally important, theheating of the parts does not reduce the freedom or ease with which thecarbon shoes slide over the olished metal surface of the drum. In act,this sliding action is perfectly free and easy under all conditions, andeven better after the clutch has been in operation for some time and hasbecome heated.

What I claim as my invention is 1. Apparatus for charging a storagebattery,'comprising a battery, a variable speed source of power, agenerator connected with said battery, and means including a centrifugalfriction clutch for driving said generator at proper speed from saidsource of power, said clutch having carbon-to-metal wearing elements toprevent the heat of friction from increasing the speed of saidgenorator.

2. Apparatus for charging a storage battery, comprising a battery, avariable speed source of power, a generator connected with said battery,and means including a centrifugal friction clutch for driving saidgenerator at proper speed from said source of power, said clutch havingwearing elements composed of substances to prevent the heat of frictionfrom increasing the speed of said generator.

3. Apparatus for charging a storage battery, comprising a battery, avariable speed source of power, a generator connected with said battery,and means including a centrifugal friction clutch for driving saidgenerator at proper speed from said source of power, said clutch havingwearing elements composed of substances including graphite to preventthe heat of friction from increasing the speed of said generator,

Signed by me at Boundbrook, Somerset Co., N. J this 2nd day of November,1914.

WILLIAM T. HENSLEY.

Witnesses;

FLORENCE A. Hosmno, E. R. FULLER.

